FIG. 10 illustrates a lateral cross section of a known side view light-emitting diode 50, including a base 51, a chip 53 mounted on the base 51, a upper sidewall 52A and a bottom sidewall 52B for blocking and/or reflecting light from the chip 53 (some types of light-emitting diodes have right and left sidewalls), and filling material 54.
Light striking the sidewalls 52A and 52B at about 90 degree (as shown by the arrow) likely moves back and forth between the chip 53 and the upper sidewall 52A, and/or the chip 53 and bottom sidewall 52B, and accordingly is confined within the light-emitting diode. Furthermore, due to the miniaturizing light-emitting diode 50, the light penetrating the decreasing thickness may result in a leakage. In practice, by above reason or others, the light extraction efficiency of a packaged chip likely drops 40% in comparison with a bare chip.
Moreover, the decreasing spacing between the sidewalls of the miniaturizing light-emitting diode also causes the difficulty in filling the space with the filling material 54 and generates voids accordingly. Therefore, the light may be trapped inside the voids, and the light extraction efficiency is reduced.